顶空气相色谱法测定浓海水中挥发性卤代烃

采用顶空法分离并富集海水淡化排放的浓海水样品,用气相色谱法测定样品中的挥发性卤代烃,通过优化顶空时间、顶空温度、水样盐度等条件,提高顶空富集效率,使方法在2.00μg/L~100μg/L范围内线性良好,相关系数均0.999,方法检出限为0.019μg/L~0.052μg/L。标准溶液平行6次测定结果的RSD为3.9%~9.6%,加标回收率为80.5%~125%。     

顶空-气相色谱-质谱法测定土壤中卤代烃

建立顶空-气相色谱-质谱法同时测定土壤中挥发性及半挥发性卤代烃的方法。实验优化顶空平衡温度、顶空平衡时间及盐度条件,并对优化后方法的线性、检出限、精密度及回收率进行分析。结果表明:29种目标化合物在线性范围内线性良好,相关系数均大于0.997,方法检出限为2.2~5.9μg/kg,样品不同浓度水平加标回收率范围为80.0%~120%,相对标准偏差小于20%。该方法适用于土壤样品中挥发及半挥发性卤代烃的测定。     

顶空-气相色谱/质谱法测定土壤中挥发性有机物

本方法采用静态顶空进样技术对土壤样品进行处理,利用气相色谱质谱联用对土壤中挥发性有机物(37种)进行了测定分析,通过测定得到最低检出浓度为:0.39～1.76μg/kg;加标回收率为:69.8%～110.2%;RSD为:3.1%～10%。本实验分析时间短,操作简单,灵敏度及测定结果较为满意。     

顶空毛细管柱气相色谱法测定水中卤代烃的研究

以顶空气相色谱法测定水中四种卤代烃,采用电子捕获检测器(ECD),内标法定量。探讨了色谱柱、热浴温度、平衡时间对测定结果的影响。结果表明,采用DB-624色谱柱,样品热浴温度为80℃,平衡时间为60min时,各卤代烃测定效果好。方法检出限为0.15~0.28μg·L-1,回收率在96.8%~99.3%之间,相对标准偏差在3.78%~5.62%之间。该法具有操作简单,准确度、灵敏度较高的特点,可用于水中卤代烃的测定。     

挥发性卤代烃顶空法毛细管气相色谱分析方法

本文应用顶空法毛细管气相色谱分析挥发性卤代烃,具有干扰少,分离效果好,分析速度快,线性范围宽等优点.此分析方法不但适用于地表水和自来水的分析,也适合废水中挥发性卤代烃的分析.     

室温平衡顶空气相色谱法测定水中挥发性卤代烃影响因素的研究

对室温下用顶空气相色谱法测定水听军发性卤代烃的影响因素进行了研究，结果表明，随着样品浓度的增高，平衡时间缩短；气液平衡瓶体积增大，平衡时间加长；同一瓶样品重复进样次数不得多于2次；适宜的气液体积比为1：2。室温平衡顶空气相色谱法简单易行。     

毛细管气相色谱法同时测定水中的7种挥发性卤代烃

用毛细管气相色谱法同时测定饮用水中7种挥发性卤代烃的研究．实验表明，该方法前处理简单，测定方便，具有较好的灵敏度、准确度和精密度，结果令人满意．样品的加标回收率在90％～110％，相对标准偏差小于5％．     

土壤中挥发性芳香烃的顶空前处理方法研究

本方法针对土壤中挥发性芳香烃顶空前处理条件进行了研究,优化了顶空密封垫的选择、顶空平衡温度、加热平衡时间、进样时间和顶空瓶压力等顶空前处理条件,测定条件科学、准确,完全能够满足土壤中挥发性芳香烃监测分析的灵敏度和准确度相关的技术要求。该方法精密度为1.7%~9.8%,准确度为34.3%~83.7%,检出限为2.0~4.2μg/kg。为制订土壤中挥发性芳香烃监测分析方法提供了技术支持。     

顶空气相色谱/质谱法测定水中四乙基铅的关键因素研究

采用顶空气相色谱/质谱法联用技术测定水中的四乙基铅,对涉及的关键操作环节及重点技术问题进行了研究。结果表明,在避光条件下于4℃低温冷藏并密封保存,添加甲醇作为保护剂,保存时间不应超过3 d。实验选择进样口温度为220℃,顶空瓶压力为96.52 kPa,调节载气流量设置实际分流比为51,可以有效改善顶空进样测定样品时存在的不出峰、不稳定或灵敏度降低的问题。对地表水、自来水及生活污水实际样品进行四乙基铅测定和加标回收分析,加标回收率为81.0%~110%,相对标准偏差(RSD)为2.5%~7.4%,能够满足《水质四乙基铅的测定顶空/气相色谱质谱法》(HJ 959—2018)的测定要求。将顶空进样法与吹扫捕集法进行比较,结果表明顶空进样法稳定性更好,适合大批量四乙基铅样品的连续测定。     

吹扫捕集气相色谱质谱法测定土壤中挥发性有机物

建立了吹扫捕集气相色谱质谱法同时测定土壤中卤代烃类、苯系物类、氯代苯类等二十多种挥发性有机物.使用模拟土壤和实际土壤样品优化了吹扫时间、吹扫温度等参数;采用内标法绘制了校正曲线,各目标化合物5个浓度水平的响应因子的相对标准偏差均小于20%,相关系数均大于0.999;测定了方法检出限,采用2g土壤,各目标化合物方法检出限界于0.02～1.00μg/kg;对两种总有机碳含量的实际土壤样品进行了加标回收实验,回收率范围64%～123%.     

固上顶空气相色谱法测定樟脑和萘

本文对固上顶空气相色谱法的理论和测定条件进行了研究。用于樟脑和萘的测定,最小检出量达１０－９ｇ,回收率为９６．０～１０１．３％．本法基体干扰小,操作简便．     

气相色谱-质谱法表征炼油厂外排废水中的有机组分

将水中的有机组分划分为悬浮性有机物(SOC)、溶解性可吸附有机物(EOC)及溶解性不可吸附有机物(NEOC)三类.分别用G3型耐酸滤过漏斗及GDX-502树脂分离和富集了某炼油厂生化处理外排废水中的SOC及EOC,漏斗滤出的和GDX-502树脂富集的有机物分别用二氯甲烷洗脱和Soxhlet提取,提取物经干燥、浓缩后,用GC/MS进行分析.结果表明该废水TOC为27.4mg/L,SOC、EOC及NEOC分别占44.5%、28.1%及27.4%.SOC中共鉴定出有机组分44种,包括正构烷烃21种、异构烷烃15种、烯烃6种及环烷烃2种,其中Ci5-C28正构烷烃的含量相对较高;EOC中共鉴定出有机组分78种,包括脂肪烃18种、芳烃12种、苯酚类10种、吡啶类7种、醇6种、酮10种、醛2种、酞酸酯3种及其它化合物10种,其中苯酚类、邻苯二甲酸正丁酯及1-甲基环己醇含量相对较高.     

顶空便携气相色谱测定水中苯系物

研究了分配常数、气液相比、温度和无机盐等对顶空分析灵敏度的影响.结果表明,这些参数对不同组分顶空灵敏度的影响有显著差异.气液相比对分配常数小的组分影响大,而温度和无机盐对分配常数大的组分影响大.提出了静态顶空/吸附热解吸/SENTEX便携气相色谱仪/微氩离子检测器测定水中4个苯系物的方法,平均相对标准偏差7.38%,平均相对误差3.46%,与标准方法比较,没有显著差异,而方法检出限低于标准方法1～2数量级.     

Workplace monitoring for volatile organic compounds using thermal desorption-gas chromatography-mass spectrometry

The interest in the identification of volatile organic compounds in the workplace has been a major focus of many National Institute for Occupational Safety and Health (NIOSH) field studies. A primary technique for sampling and analysis of these compounds is summarized by NIOSH Manual of Analytical Methods (NMAM) 2549. This is a screening method that uses a multi-bed sorbent to trap a wide variety of compounds and compound classes. Thermal desorption techniques are used as a first attempt to characterize potential contaminants in a workplace and to determine what future sampling and analyses must be performed. Field examples are provided to show the versatility of thermal desorption methods and techniques. Due to their sensitivity, thermal desorption tube methods are sometimes required in order to measure the workplace concentrations of unusual compounds. In other situations, the exposures are too high or varied to make thermal desorption tubes practical. In these cases, the identification of contaminants with thermal desorption tubes leads to new method developments for the quantification of specific compounds using more conventional solid sorbent-solvent desorption based methods.     

Solid-phase microextraction coupled to gas chromatography-mass spectrometry for the study of soil adsorption coefficients of organophosphorus pesticides

A solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) method for the simultaneous determination of the organophosphorus pesticides (OPPs), phorate, diazinon, methyl-parathion, fenitrothion, malathion, fenthion, ethyl-parathion and methidathion, has been developed to study their soil/water distribution. The method was used in conjunction with a conventional 'batch equilibrium method' to assess the soil adsorption coefficients (Koc) of the target compounds in different soil samples with known organic carbon content. Contrary to traditional techniques, the present method is fast, solvent-free and highly sensitive, thus permitting the assessment of the Koc values of the target compounds even at low soil concentration levels, close to those encountered in real field contamination, where the Freudlich adsorption isotherms can be considered to be linear. The estimated Koc values were found to be in good agreement with those reported in the literature.     

环境空气中痕量挥发性有机硫监测分析方法研究

采用预浓缩系统与GC MS联用,建立了环境空气中痕量挥发性有机硫的分析方法,该法用苏玛罐或Tedlar袋采集空气样品在预浓缩系统中经液氮于-160℃冷冻浓缩后,进入GC MS进行分析。甲硫醇、乙硫醇、甲硫醚、乙硫醚、二甲二硫的最低检出限分别为2 0、1 0、1 0、1 0、0 5μg m3。经6次的重复测定,其相对标准偏差小于9 0%。该方法已用于环境空气的测定,取得了令人满意的结果。     

Determination of N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) in the general population using gas chromatography-mass spectrometry

Carbamoylation of glutathione, peptides and DNA is thought to be one of the most important reactions occurring in an organism after exposure to nitrosoureas, methylformamides or isocyanates. The carcinogenic effects of carbamoylation are not yet fully clarified. Although carbamoylation is known to occur after occupational exposure, it has never been reported in the general population. To clarify the situation, we investigated the levels of N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) in urine samples from persons without occupational exposure using a sensitive and specific method (gas chromatography-mass spectrometry, GC-MS). AMCC is the degradation product of N-methylcarbamoylated glutathione. The clean-up procedure of urine samples includes two liquid-liquid extraction steps and solid phase extraction using a cation-exchange resin to separate AMCC from other urinary components. N,N-Dimethylpropionic acid amide (DMPA) is used as internal standard. During the preparation of the samples, AMCC is converted to ethyl-N-methylcarbamate (EMC) in the presence of anhydrous potassium carbonate (K2CO3) and ethanol. The reliability and accuracy of this method have been proven in detail. The relative standard deviation for the within-series imprecision for three different concentrations was determined to be between 10.9% and 14.3%, while the relative standard deviation for the between-day imprecision was between 11.3% and 14.8%. The mean recovery for AMCC was determined to be between 79.2% and 85.6%. The limit of detection for the simultaneous measurement of two fragment masses was 30 micrograms L-1. Using this GC-MS method, we analysed urine samples from 42 individuals of the general population in order to determine their urinary excretion of AMCC. It was identified in 40 samples. The mean concentration was 40 micrograms L-1. AMCC can be formed in two ways. The first possibility is the dietary intake of isothiocyanates, especially methyl isothiocyanate, which is a component of wine and cruciferous vegetables (such as cabbage, turnips and cress). During the metabolism of isothiocyanates in humans, the sulfur is partly exchanged for oxygen resulting in the formation of the corresponding isocyanate derivatives. The other possibility is the physiological formation of AMCC. In humans, this may occur via a two step process: carbamoylation and methylation, or vice versa. However, as AMCC was identified in about 95% of urine samples, and the standard deviation for the level of AMCC excreted was low, physiological formation seems to be the more probable pathway.     

双道氢化物原子荧光法测定水和土壤中的砷

用AFS-2201双道氢化物发生原子荧光法测定水、土壤样品中的砷含量,方法简捷、快速、准确,二次污染物少.HNO3浓度大于5ppm时,对测量结果有影响.主机通过与微机相联可直接得出监测数据,大大减轻了监测人员的工作量,测定结果令人满意.     

空气中挥发性有机物(VOCs) 的监测方法研究

建立了热脱附仪和气相色谱-质谱联用测定室内空气和环境空气中35种挥发性有机污染物的分析方法,方法的最低检出限为0.1～0.9μg/m3, 20μg/m3挥发性有机物标准经6次的重复测定,其相对标准偏差小于8.4%.该方法已用于室内空气和环境空气的测定,取得令人满意的结果.     

吹扫捕集与气相色谱-质谱联用测定饮用水和地表水中挥发性有机污染物

报道了Trap I(VOCARB 4000)柱捕集水中挥发性有机污染物的性能和条件,建立了吹扫捕集和气相色谱-质谱联用测定饮用水和地表水样中25种挥发性有机污染物的分析方法.水样的加标回收率在90%～110%之间,最低检测限在0.04～0.85μg/L之间,20μg/L的挥发性有机物标准溶液经重复6次测定,其相对标准偏差基本小于5.0%.该方法已成功地运用于饮用水和地表水中挥发性有机污染物的测定,结果令人满意.